Schaller Classical Guitar MachinesHigh quality 16:1 Hauser-style tuners for nylon-string classic guitars with slotted peghead and 1-3/8" (35mm) string roller spacing.The roller sleeves are durable 3/8" (9.53mm) diameter white plastic. The knobs are handsome pearlescent plastic or genuine polished ebony.Each set includes a pair of 3-left/3-right tuning machines with mounting screws.Installation TipsPeghole spacing: Plate-mounted tuners can't work efficiently if the pegholes are improperly aligned. Our Tuning Machine Drill Jig for Slotted Pegheads ensures the correct 1-3/8" string roller spacing for accurate tuning.Mounting screws: Pilot holes required. Installing delicate screws into hard wood requires great care and accuracy. We highly recommend the #1712 Depth-stop Drill Bit (5/64" bit) for the pilot hole before installing these screws. Lubricate the screw threads with cutting lubricant (also wax or a bar of soap) to reduce friction and help them thread properly.Schaller Slotted Classical Guitar Machines - High Quality 16:1 Hauser-style Tuners For Nylon-string Classic GuitarsThe Roller Sleeves Are Durable 3/8" (9.53mm) Diameter White Plastic.The Knobs Are Handsome Pearlescent Plastic Or Genuine Polished Ebony.Installation Tips - Peghole Spacing: Plate-mounted Tuners Can't Work Efficiently If The Pegholes Are Improperly Aligned. Our Tuning Machine Drill Jig For Slotted Pegheads Ensures The Correct 1-3/8" String Roller Spacing For Accurate Tuning.Each Set Includes A Pair Of 3-left/3-right Tuning Machines With Mounting Screws.